There are innumerous situations wherein the emission of bodily fluids presents problems in day-to-day life. Types of bodily fluid include, but are not necessarily limited to: perspiration, menstrual flow and other vaginal discharges, urine and fecal emissions, salivation and nasal emissions, lactation in nursing females, and nocturnal emissions. Involuntary emissions often lead to embarrassing situations where they exude through and are visible on clothing and/or result in transmission of odours. Many proposals have been offered for dealing with these problems and these can be categorized broadly into solutions involving emissions of large or small volumes. Large volume emissions such as infant urinary and fecal excretions, incontinence and heavy menstrual flow typically require the use of highly absorbent materials, for example in the form of diapers for both adults and infants, and feminine hygienic products such as tampons, pads and liners, to retain the emitted matter until the absorbent can be removed and, if necessary, replaced. Oftentimes, such products are disposable for convenience or because the absorption changes the structure of the product so that it cannot be reused. Typically, these products are relatively conspicuous due to their bulk or noise they might generate (i.e. in the case of adult diapers) when moving about.
Smaller volume emissions involving light menstrual flow or excreta are sometimes also handled in similar manners. When emissions are expected in cases involving mild intermittent incontinence or nearing the commencement of the menstrual cycle, such products are typically used as a precaution merely to avoid the consequences. When no emissions occur, the article is still disposed of for hygienic reasons which results in unnecessary costs to the consumer and an additional burden on our environment, even where the products are biodegradable.
The prior art reveals that there are numerous products designed for collecting and maintaining women's menstrual flow or body fluid of incontinence and reference may be made to the following U.S. Pat. Nos. 5,429,627 dated Jul. 4, 1995 to Johnson et al; 5,429,311 dated Jul. 4, 1995 to Tel-Aviv et al; 4,678,465 dated Jul. 7, 1987 to Avejic; 5,069,672 dated Dec. 3, 1991 to Wippler et al; 5,368,585 dated Nov. 29, 1994 to Dokken; 5,342,340 dated Aug. 30, 1994 to Kichefski; and 5,261,901 dated Nov. 16, 1993 to Guay. The products described in these patents are designed for use with different magnitude of flow or leakage, which frequently cause embarrassing markings (strike-through) and/or troublesome cleanups. Moreover, there are periods of time when there is uncertainty as to whether light flow, not only menstrual flow but discharge due to incontinence, may occur when pads or tampon type products are not being worn.
While mild perspiration is typically evaporated through many clothing fabrics, heavy perspiration can wet materials and thereby become visible and leave perspiration stains after evaporating from the cloth. Washable or disposable panels are often attached to clothing articles to absorb these minor emissions such as, for example, armpit panels to absorb excess perspiration and inserts for nursing bras.
Nighttime emissions (i.e. during sleep) can result in soiled or wetted bedding. The bodily fluids may soak through the linen and into the mattress or may become trapped against the person's skin for a long period of time before the person wakes up, which may result in skin irritation and increased odour. Where emissions during sleep are expected, it is often the solution to provide so-called “rubber sheets” which tend to be both liquid and vapour impermeable. While such solutions prevent the emissions from soaking into the mattress, they do not necessarily permit ready evaporation of the liquid.
In the medical field, it would be useful to have a protective garment which prevents bodily fluids from others which might come into contact with the garment from being transmitted through the garment yet which enables certain bodily fluids of the wearer, such as perspiration, to be evaporated.
Research has showed that there are numerous publications and patents on absorbent diapers, napkins and pads for incontinence, all of which are designed to be disposed once soiled. However, there has been little progress towards non-disposable or launderable absorbent undergarments or materials therefor. E. Lees [Wuagneux Nonwovens Industry 28/9, p 104-106, 1997] found that the sales of absorbent underwear have been rising in the adult incontinence market. There have also been some new innovations in the market, including an absorbent undergarment like regular underwear, which is expected to attain increased sales in the future. There is also a growing trend in odour control products.
As mentioned above, a hygienic absorbent undergarment must be capable of preventing leakage or strike through from body fluid flows which are not necessarily of great quantity and be of great comfort. Accordingly, a primary distinguishing feature of a reusable undergarment would be in the use of special materials to maintain a high degree of comfort for the wearer as well as the necessary structural and functional integrity to endure multiple cycles of use and washing. For example, while the thickness of reusable diapers typically range from 2.0 to 2.5 mm and even up to 5.0 mm, a material for an absorbent undergarment should be on the order of 0.5-1.5 mm to not only remain inconspicuous, but to be visually equivalent to normal wear undergarments.
Preferably, these garments should be virtually indistinguishable from normal undergarments in both comfort, wearability, durability, and style.
In the market, there exist reusable absorbent undergarments consisting of two layers or three layers. Two layer undergarments contain an inner layer and outer layer. The inner layer has the characteristic of being liquid permeable so as to allow the body fluids to flow into it and be absorbed. The outer layer has the characteristic of being liquid impermeable but air permeable, so that the liquid absorbed in the inner layer does not strike through the outer layer. The breathability of the outer layer also reduces wet feeling and will in fact allow some evaporation of liquid collected in the inner layer. An example of such two layer undergarments is provided by way of Applicant's Canadian Patent No. 2,149,477, issued Apr. 8, 1997 and its pending U.S. patent application Ser. No. 08/971,327 filed Nov. 17, 1997, the disclosures of which are hereby incorporated by reference in their entirety. In general, these documents describe a garment in the form of an undergarment or an outerwear which has a body conforming lower torso portion for preventing leakage of body waste liquids. The torso portion is formed of sheet material which at least in the crotch portion consists of a liquid permeable inner layer and a juxtaposed outer layer which is breathable but liquid impermeable. Bodily fluids which come into contact with the liquid permeable inner layer pass into or are absorbed by the inner layer and which fluids subsequently come into contact with the outer layer. Since the outer layer is vapour permeable but liquid impermeable, the liquid which has been held inwardly of the inner layer (and away from the wearer's skin) is permitted to evaporate to a certain extent.
To increase the capacity of absorbency, it is known to insert an absorbent layer inserted in between the inner and outer layers. A reusable brief from Roche Product. Limited [Medical Textiles January, p 3, 1994; Medical Textiles January, p 3, 1993] is an example of three layer undergarment, which has a cut away high leg shape and lace trim for an active lifestyle. It contains a rounded insert made from the special absorbent KYLIE™ for providing an effective absorbency of 50-75 milliliters per gram absorbent. However, three-layer systems not only require an additional constituent, but also involve a more complex manufacturing process.
For those products which need more comfort and which are not necessarily of great absorbency, two layer undergarments are proposed by different studies. C. L. Weimer [Medical Textiles December, p 9-10, 1997] described an undergarment made of polyurethane coated nylon with moderate absorbency. U.S. Pat. No. 5,300,053 dated Nov. 4, 1991 to D. M. Genaro describes a two layer brief with a liquid impervious layer and a liquid pervious layer. However, the composition of two layers was not specified.
In early days, the outer layer was typically made from polyethylene [U.S. Pat. No. 5,520,673 dated May 28, 1996 to Menasha et al], polypropylene [U.S. Pat. No. 4,518,451 dated Sep. 2, 1982 to T. J. Luceri] or polyvinylchloride (PVC). These materials are liquid impervious as well as air impermeable. Nowadays, air permeable but liquid impervious materials are used more and more, such as a polyurethane coated knitted polyester [U.S. Pat. No. 4,352,356 dated Oct. 5, 1982 to D. P. Tong] or a polyurethane coated non-woven as a liquid impervious panel for urinary incontinence garment [U.S. Pat. No. 5,085,653 Feb. 4, 1992 to H. Levy; Anonymous Vliesstoff Nonwovens International No. 5, p 163, 198, 1989]. Kuner Textilwerke GmbH [Anonymous, Techtex Forum No. 7-8, p 184, 1993] developed a new medical fluid barrier named Humiditex™ which is a polyurethane based membrane. It can be used in conjunction with all types of textile materials and served as operating apparel, bedsheets, incontinence products, diapers and underwear. Gore-Tex™ is a porous membrane made of polytetrafluoroethylene (PTFE). It has good air and moisture vapour permeability but it is liquid impervious. To economize the products, other kind of porous membranes are used to replace Gore-Tex™. ECTFE (polyethylene-chlorotrifluoroethylene) [Ausimont Halar ECTFE Fluoropolymer Guide USA 1997] membrane has excellent moisture vapour permeability as well as high tensile strength, elongation and flexibility.
To obtain high efficiency of reusable absorbent, some interesting materials have been developed. U.S. Pat. No. 5,360,421 dated Aug. 16, 1993 to D. W. Revelle describes an absorbent textile garment with bicomponent textile liner. The liner next to wearer's skin is a knitted bicomponent textile to provide a material having a nylon face and an opposite polyester face. The hydrophilic nylon is a copolymer of nylon 6 and polyethylene oxide diamine (product Hydrofil™ of Allied Signal Inc.). The moisture or the liquid is transferred from polyester side to nylon side. So that the liner has the function of both absorbing and maintaining a high degree of comfort for the wearer even after it has been wetted. Some modified polymers can be used as a super absorbent. A fabric capable of absorbing large amounts of water is produced by the basic hydrolysis of polyacrylonitrile fibers [U.S. Pat. No. 4,337,328, 1982 to Holst et al]. U.S. Pat. No. 4,411,660 dated Apr. 14, 1982 to F. S. Dawn] describes a super absorbent with high molecular weight acrylic polymer containing hydrophilic carboxylate groups. However, the polymer forms a gel on contacting with aqueous solutions. An absorbent comprising of a blend of antimicrobial acrylic fibers and hydrophilic cellulosic fibers is taught in U.S. Pat. No. 5,562,648 dated Mar. 31, 1995 to R. H. Peterson. In Peterson's U.S. Pat. No. 5,350,625 dated Jul. 9, 1993, he mentions that 35/65 acrylic/rayon fabric has a good absorbency as well as a good retention. Phosphorylated or acrylamide grafted cellulose has an ability of ion-exchange [M. Weltrowski and R. Toupin Fabric Formation 1996 pp 71-75], which can be used to remove the odours of urine [Japan JP 62,237,924 dated Oct. 17, 1987 to H. Simizu; Japan JP 62,298,359 Jun. 18, 1986 to T. Fujii] and maintain the desirable acidic pH to control the infection and inflammation in women's underwear [V. G. Zaikov Polymer Degradation and Stability No. 36, 1992 pp 49-52].
Some patents are related to design of the absorbent undergarments. An ingenious design can impart good qualities to the underwear. Stretchable openings at waist and legs are described in U.S. Pat. No. 5,683,374 dated Apr. 23, 1996 to M. Yamamoto; and U.S. Pat. No. 4,847,134 dated Dec. 22, 1987 to A. M. Fahrenkrug; or guards at the side of the pads [Anonymous, Nikkei Weekly No. 1688:20, P 33, September 1995] prevent leakage.
With all this activity and the potential for such products, the market has yet to experience a material or a product which is genuinely reusable and which is not evident that it is a product designed for such purposes. As indicated above, the thickness alone in many prior art attempts gives an institutional or “adult diaper” appearance and the level of comfort is much to be desired.
There is, therefore, a need for a liquid impermeable fabric material Mich permits the absorption and retention of minor volumes of liquids while the liquid is allowed to evaporate.
Further, there is a need for such a material from which articles can be manufactured which have effectively the same appearance and level of comfort as the articles they intend to replace, yet provide functional features not available with such articles.
There is also the need for a material from which garments, undergarments, outerwear, swimwear, active wear, and work wear can readily be assembled without the need for specialized equipment and which material is capable of absorbing or drawing a bodily fluids away from the wearer's skin for evaporation without penetration of the fluid through the entire thickness of the material. Furthermore, there is a need for such a material which closely conforms to typical materials in wearability and washability. There exists the need for such a material which can be used as the fabric for the garments themselves or as a functional lining in such garments.
There is further a need for a reusable (i.e. launderable) material which can be incorporated into garments for discretely dealing with minor bodily fluid emissions and which functions to prevent embarrassing situations or to alleviate issues of self-consciousness when worn. Such a material should be stain resistant. More specifically, there is the need for a material which can be fashioned into hygienic undergarments which are virtually indistinguishable from normal undergarments in comfort, wearability, durability, and style. Such a hygienic undergarment and should be capable of preventing leakage from body fluid flows which are not necessarily of great quantity and may be worn either in combination with existing protective products or alone. It is also desirable to provide comfort while not being conspicuous.